Hydrochloric Acid-oxygen Leaching and Metal Recovery from a Copper- nickel Bulk Sulfide Concentrate.
Smyres-GA; Lei-KPV; Carnahan-TG
Reno, NV: U.S. Department of the Interior, Bureau of Mines, RI 8999, 1985 Jan; :1-17
The Bureau of Mines investigated a HCl-0 sub 2 leaching procedure to recover Cu, Ni, and Co from a low-grade bulk sulfide flotation concentrate prepared from the Dulurh gabbro complex. Since the Duluth gabbro complex is the largest known and unexploited Ni resource in the United States, the development of options for extracting the metal values from the flotation concentrate of the domestic resource is necessary. Conditions were determined for producing a pregnant solution low in Fe to facilitate recovery of the metal values. Leaching experiments were conducted at 15 pct solids, 100 to 120 C 0.2 to 0.3 g HCl per gram concentrate in a 50-gal reactor pressurized to 50 psig with 0 sub 2. Base metal extractions from the concentrate were, in percent. 90 to 92 Cu, 99 Ni, 97 to 99 Co, and 0.1 Fe. Precious metals extractions were erratic and unpredictable: at best their extractions were, in percent, 55 Au. 90 Ag, 40 Pt. and 45 Pd. The reaction time at 120 C was 0.5 h. The use of compressed air instead of O sub 2 as the oxidant was also investigated. Solvent extraction using LIX 622 was used to remove Cu from the pregnant solution. Cementation on Cu was tested for precious metals recovery, while sulfide precipitation was used to produce a Ni-Co product. A conceptual flowsheet for treating the Duluth gabbro concentrate is proposed.
Gabbro; Hydrometallurgy; Precious-metals; Hydrochloric-acid; Leaching; Copper; Cobalt; Nickel
IH; Report of Investigations
Reno, NV: U.S. Department of the Interior, Bureau of Mines, RI 8999